|Poll company|Source|Publication date|PSUV|Opposition|Undecided|
|---|---|---|---|---|---|
|GIS XXI|Radio Nacional de Venezuela|March 2010|32|22|36|
|GIS XXI|Radio Nacional de Venezuela|May 2010|36|23|33|
|GIS XXI|Radio Nacional de Venezuela|June 2010|44|20|-|
|Hinterlaces|Hinterlaces El Universal|July 2010|27|28|23|
|GIS XXI|Correo del Orinoco|August 2010|50|44|N/A|
|IVAD|El Universal|August 2010|45|43|N/A|
|Keller & Asociados|El Universal|August 2010|32|46|N/A|
|Keller & Asociados|El Universal|2 September 2010|43|57|0|
|Datanálisis|ABC.es|September 2010|52|48|N/A|
|Hinterlaces|Unión Radio Descifrado|September 2010|41|37|N/A|
|IVAD|Unión Radio Descifrado|September 2010|54|46|N/A|

Question: how many different poll companies are listed?
Answer: 5